Fibromyalgia is a disease which develops, for example, unexplained pains, insomnia, neuropsychiatric symptoms, irritable bowel syndrome and cystitis as prominent symptoms. In recent years, fibromyalgia, which is accompanied by mucosal system disorders (dry eye, dry mouth) and enthesitis, have been discovered. Meanwhile, the cause of fibromyalgia has not been revealed. Therefore, therapeutic agents for fibromyalgia are demanded now.
For example, WO 2008-041751 A1 discloses a therapeutic agent for fibromyalgia accompanied by enthesitis, which contains salazosulfapyridine as an active ingredient.
WO 2007-052125 A2 discloses a therapeutic agent for hypermyotonia-type fibromyalgia, which contains pregabalin as an active ingredient.
WO 2009-139470 A1 discloses a therapeutic agent for hypermyotonia-type fibromyalgia, which contains pilocarpin hydrochloride as an active ingredient.
Meanwhile, etanercept is manufactured and sold under the trade name “Enbrel” (registered trademark) as a therapeutic agent for rheumatoid arthritis (an attached document of “Enbrel” (registered trademark) for subcutaneous injection). Etanercept is a soluble TNF receptor (JP 2721745 B2, JP 2728968 B2, and JP 2960039 B2).
Non-Patent Literature 2 (ORTEGA, E. et al, Aquatic exercise improves the monocyte pro- and anti-inflammatory cytokine production balance in fibromyalgia patients, Scand J Med Sci Sports, 2010, Vol. 1193, No. 1, p. 1-9) shown below discloses a hypothesis that the amount of an inflammatory cytokine, such as a TNFα, risesin fibromyalgia patients (excluding rheumatoid patients). However, this matter is just a hypothesis, and it is not mentioned that the reasons for the increase of the amount of an inflammatory cytokine such as a TNFα in certain fibromyalgia patient is associated with fibromyalgia. In Non-Patent Literature 2, it is not demonstrated that an inflammatory cytokine such as TNFα is a cause of pains in fibromyalgia. In Non-Patent Literature 2, nothing is disclosed about a knowledge concerning the increase or decrease in TNFα levels and fibromyalgia. Further, in Non-Patent Literature 2, it is not demonstrated in any way that the inhibition of an inflammatory cytokine such as TNFα is effective for the amelioration of pains in fibromyalgia and the like.
In Wyeth Kabushiki Kaisha, Enbrel 25 mg for subcutaneous injection, Interview form for pharmaceuticals, 2007, 6th edition, 1-57 (Non-Patent Literature 3 shown below), it is described that etanercept has an inhibitory activity on TNFα and that etanercept is effective for the treatment of inflammation-dependent pains in rheumatoid or the like, and an etanercept-containing preparation for injection is disclosed.